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171.
A novel approach for the synthesis of 2,4-dialkyl-3-hydroxybutanolides, having three successive stereogenic centers, by an acid-catalyzed ring-switch reaction of 2-(2-hydroxyalkyl)lactams is described. This transformation was applied to the synthesis of the key intermediates of teromerase inhibitor UCS1025A. 相似文献
172.
173.
Takehiko Uematsu Yoshiaki Matsui Shusuke Kakiuchi Akira Isogai 《Cellulose (London, England)》2011,18(4):1129-1138
Carboxymethyl cellulose (CMC)-rich cellulose sheets were prepared with a cationic retention aid, poly[N,N,N-trimethyl-N-(2-methacryloxyethyl)ammonium chloride] (PTMMAC), using a papermaking technique. When 5% PTMMAC and 5% CMC were added to
cellulose slurries, approximately 94% of the polymers were retained in the sheets by formation of polyion complexes between
the two polymers. When the PTMMAC/CMC/cellulose sheets were soaked in solutions consisting of ethanol, water and calcium chloride
(EtOH/H2O/CaCl2) with a weight ratio of 75:24:1, almost all PTMMAC and CMC molecules remained in the sheets, forming the structures of PTMMAC-N+Cl− and CMC-COO−Ca2+Cl− without dissolution of these molecules in the soaking solution. Thus, PTMMAC, CMC and calcium contents in the sheets were
able to be determined on the basis of these PTMMAC and CMC structures from analytical data such as nitrogen, calcium and chlorine
contents. The trade-off properties between sufficient wet strength in use and water-disintegrability after use can be added
to the PTMMAC/CMC/cellulose sheets by selecting weight ratios of the EtOH/H2O/CaCl2 solution used as the impregnation liquid. 相似文献
174.
Yusuke MizutaniHiroki Tanimoto Tsumoru MorimotoYasuhiro Nishiyama Kiyomi Kakiuchi 《Tetrahedron letters》2012,53(44):5903-5906
Double nucleophilic N-alkylation of α-oxime-esters, affording N,N-dialkyl-α-amino acids is herein described. Grignard reagents accomplished double N-alkylations via umpolung and various N,N-dialkylated α-amino acids were successfully synthesized in 15 min. Both electron-withdrawing sulfonyl groups and electron-donating silyl and methyl groups on oximes were available. Alkylmagnesium species and (E)-configuration of α-oxime-ester were essential to this cascade reaction. 相似文献
175.
We study the origin of a sudden change of the radius of oxygen isotopes at 23O in terms of a coupled-channel model approach. We use the cluster-orbital shell model approach for describing the system. Qualitatively, the sudden change of the radius can be understood as the competition of occupation of the valence neutrons and the component of the core configuration. For the 23O case, the effect of the partially Pauli-forbidden states of the 1s 1/2-orbit is small in the excited-core configuration. 相似文献
176.
Akihiro Nomoto Atsushi Kido Kiyomi Kakiuchi Ikuko Mitani Masahiko Tatsumi Akiya Ogawa 《Research on Chemical Intermediates》2009,35(8-9):1027-1032
Nanoparticles were obtained by the reaction of SmCl3·6H2O with sodium borohydride (NaBH4) in the presence of sodium polyacrylate (PAA) with average molecular weight of 5,100 as a capping polymer. The resulting colloidal solution was placed on a Cu grid and characterized by transmission electron microscope (TEM) measurement, which clearly indicated the generation of nanoparticles. The reaction of LaCl3 with NaBH4 in the presence of PAA led to preparation of lanthanum nanoparticles, similarly as samarium nanoparticles. 相似文献
177.
178.
Kiyomi Itabashi 《Zeitschrift fur Physik C Particles and Fields》1985,28(4):601-605
General form of nontrivial solutions of the Wess-Zumino consistency condition is derived, and the uniqueness of the chiral anomalies is discussed. Whole of the argument is based on the algebraic treatment of the problem in the extended Euclidean space-time of the dimension higher than six. Particularly crucial to the argument is a lemma, the proof of which is presented in detail. 相似文献
179.
Superoxide (O2?) oxidized substrates having labile hydrogens to ketones in the presence of phosgene dimer. Oxidations with similar treatment of alkynes were examined. The reaction mechanism was also discussed. 相似文献
180.
We study the frustration-induced enhancement of the incommensurate correlation for a bond-alternating quantum spin chain in a magnetic field, which is associated with a quasi-one-dimensional organic compound F5PNN. We investigate the temperature dependence of the staggered susceptibilities by using the density matrix renormalization group, and then find that the incommensurate correlation becomes dominant in a certain range of the magnetic field. We also discuss the mechanism of this enhancement on the basis of the mapping to the effective S=1/2 XXZ chain and a possibility of the field-induced incommensurate long-range order. 相似文献